Lough Feeagh (Irish: Loch Fíoch) is a freshwater lake in County Mayo, Ireland. It is the largest of the lakes in the Burrishoole catchment, which consists of seven lakes and interconnecting rivers and streams. Lough Feeagh is one of the lakes observed and studied by the Global Lake Ecological Observatory Network (GLEON).

Lough Feeagh drains into Lough Furnace, which then drains through the short Burrishoole Channel into Clew Bay.

The remains of an Iron Age promontory fort named Leaba Dhiarmada agus Gráinne (Diarmuid and Gráinne’s bed) exists on a peninsula of land which reaches into the lake.

• List of loughs in Ireland

• Global Lake Ecological Observatory Network: Feeagh
• Global Lake Ecological Observatory Network: Information and photos (PDF)
• Tageo.com: Information and map
• Marine Institute of Ireland: Burrishoole Fishery